Aircraft ground and water collisions.

[YamashiroKai]

Currently aircraft use only the wreck_explosion for ground collisions, explosions in the air and when hitting the water surface. The ground_collision and plane_explosion_water events seem to be unused, and should be used instead.

I shouldn't have to say that an aircraft sounds completely different when it hits water than when it hits solid ground.

[Uchuujin01]

Hello! plane_explosion_water works, I've just checked, it should sound for player's aircraft. But you right, there should be more diversity in those explosion events. Will fix it, thank you.